If information is power, then there's no hero mightier than a librarian. Librarians are superheroes, adventurers, explorers and invaluable guides to other heroes. Here are 20 amazing librarians who save the world every day!

As Spider Robinson writes in The Callahan Touch, "Mary Kay is one of the hidden masters of the world — a librarian. They control information. Don't ever piss one off." So here are 20 librarians who you shouldn't ever piss off — but who might be a lot of help if you're in a tight corner.

Flynn Carsen in The Librarian movies on TNT

Noah Wyle, star of the upcoming Falling Skies series, also starred in these awesome TV movies. Flynn Carsen gets hired by the Metropolitan Public Library to work as a librarian — but he doesn't realize the Library has been around for centuries, and it actually protects a ton of magical artifacts. (Similar to Syfy's Warehouse 13 series and Friday the 13th: The Series.) With the help of the amazing powers of Bob Newhart and Jane Curtin, he tracks down missing artifacts and keeps the world safe from their power.

The Librarian of Unseen University Library, in Terry Pratchett's Discworld novels

A wave of magic transformed the librarian into an orangutan, and he discovered he liked being one — so he's resisted all efforts to turn him back into a human. It's rumored he was once known as Dr. Horace Worblehat, but since he's systematically destroyed all images and documentation of his former human identity, it's hard to know. The only sounds he ever utters are "ook" or "eek," but by now Rincewind and the other wizards are so used to this that they can understand him perfectly.

Lirael in the Abhorsen novels by Garth Nix

Lirael is the first of the Clayr not to inherit the gift of the Sight, in hundreds of years. With her raven-colored hair, pale complexion, pointy face and unknown parentage, she looks nothing like the fair-haired, tanned seers around her. She's horribly depressed about being so different, until she gets an appointment to the Clayr's Library on her fourteenth birthday. There, she starts to do research in forgotten corners, uncovering clues to an adventure of immense importance. She discovers a soapstone carving of a dog and accidentally sets free a powerful magic creature in the library, called a Stilken, which she finally vanquishes using the Chief Librarian's sword. She later summons the Disreputable Dog, who helps her on her quest to bind the evil Orannis once again and save the land.

Rex Libris in the Rex Libris comics

Rex Libris is the "tough-as-nails Head Librarian at Middleton Public Library," who strikes fear into recalcitrant borrowers — and also battles "loitering zombies" and alien warlords who refuse to pay their late fees. His teleportation crystals let him travel to any corner of the universe to battle evil. "With fists of steel and mind as sharp as a tack, Rex is a true guardian of knowledge, foe of the foolish, defender of the Dewey Decimal System, and the best hope for the future of civilization."

Iku Kasahara in Toshokan Sensou (Library War)

In an alternate 1989, the Japanese government passed a law allowing for the censorship of information or ideas that might be harmful to Japanese society. Now, it's 2019, and the Media Betterment Committee sends soldiers to the library to destroy works they want to censor. It's up to the militia defending the libraries, including new recruit Iku Kasahara, to save knowledge from those who would destroy it. As one person puts it, "going to library school means basic training and learning how to use a rifle to protect books." This manga series was also turned into a 12-episode anime.

Margarita Staples and other librarians in Un Lun Dun by China Mieville

All bookshelves lead to the Wordhoard Pit, a kind of nexus of libraries, in Mieville's imaginative YA novel about a distorted alternate London. The Extreme Librarians risk their lives in this universe of towering bookshelves to retrieve volumes, with picks in hand, sometimes having to battle shelf-monkeys. As Margarita says, "There are risks. Hunters, animals, and accidents. Ropes that snap. Sometimes someone gets separated."

Evelyn "Evie" Carnahan in The Mummy and The Mummy Returns

I may not be an explorer, or an adventurer, or a treasure-seeker, or a gunfighter, Mr. O'Connell, but I am proud of what I am... I am a librarian.

She travels all around the world to seek the lost Book of Amun-Ra, and finally finds the Book of the Dead. And she turns out to be pretty handy with a gun and fights against Anak-Su-Namun.

Lara in the Superman comics

Superman's biological mother was the archivist and librarian in the capital city's archives on Krypton. She "possessed a vast knowledge of Kryptonian history and culture," perhaps allowing her to include more useful information in the rocket ship that sent her son to Earth. And if you want to watch a compilation of great librarians in comics, click here. (Plus here's a great listing.)

Barbara Gordon in Birds of Prey and other comics

No mention of heroic librarians would be complete without including the former Batgirl — who worked as a librarian in Gotham City for many years (and probably had to deal with all sorts of strange reference volume requests.) Eventually, her librarian skills went fully digital and she's now the super-hacker known only as Oracle. (She also was a member of Congress for a few years, although I guess that's been retconned at this point.) If you ever doubted that information was power, you'd only have to mess with Barbara G. and you'd learn your mistake. (Batman also has a keen grasp of library science, as proved in the Peter Milligan storyline where he copes with a serial killer who is murdering people and placing their bodies according to a modified Dewey Decimal system.)

Zoe Heriot in Doctor Who

She's not just the smartest companion ever to rock a sparkly catsuit — Zoe also has an incredible brain, including total recall. Which is why, when we first meet her in "The Wheel In Space," she's working as the librarian aboard a space station, specializing in parapsychology. Of course, she needs the Doctor to explain to her that "logic, my dear, merely allows one to be wrong with authority." It also allows her to make a computer have a brain seizure just by talking to it, though. Don't mess with a librarian who's seeking information.

The virtual Librarian in Snow Crash by Neal Stephenson

As Tim Blackmore from the University of Western Ontario writes in his essay on this librarian (PDF) Hiro Protagonist's "indispensible guide and companion" is a virtual librarian, given to him by Juanita, along with half the library worth of information. Writes Stephenson:

Hiro can see a large, dimly lit room that wasn't there before . . . . A man walks into his office. The Librarian daemon looks like a pleasant, fiftyish, silver-haired, bearded man with bright blue eyes, wearing a V-neck sweater over a workshirt . . . . Even though he's just a piece of software, he has reason to be cheerful; he can move through the nearly infinite stacks of information in the Library with the agility of a spider dancing across a vast web of cross-references. The Librarian is the only piece of CIC software that costs even more than Earth [a geopolitics program]; the only thing he can't do is think.

The Librarian gets great lines like, "Sorry-but due to my internal structure, I'm a sucker for non-sequiturs," and due to his learning capacity, he's mostly programmed himself.

Luna Moth in the Escapist by Michael Chabon, Brian K. Vaughn, et al.

The other superhero created by Kavalier and Clay, creators of The Escapist, is the mistress of the night, Luna Moth. Her alter ego is Judy Dark, a quiet librarian who works in the basement of the New York City Public Library. One day, she sees a couple of criminals trying to steal a rare and magical book, and confronts them — but after a gun gets fired, a wire falls into a puddle of water, causing a surge of energy to run from the book's golden cover into Judy Dark. She's transformed into a warrior goddess who goes around zapping criminals with her green energy rays, while never quite being able to control the force of her imagination.

Elijah Bradley, The Patriot, in the Young Avengers

While working at the New York Public Library, Eli also becomes a member of the Young Avengers, following in the footsteps of his grandfather, Isaiah Bradley. He has all the powers of a super-soldier, like Captain America. Another superhero who's a librarian in his spare time is Captain Comet, who explores the stacks of his local library when he's not out exploring the universe and fighting ultimate evil.

The Cheshire Cat in Jasper Fforde's Thursday Next series

Renamed "the Unitary Authority of Warrington Cat" due to changing boundaries, this cat is the overseer in the Great Library, a library within the book world, which contains every book ever written. The Unitary Authority cat turns out to be quite helpful to Thursday in her quest.

Giles in Buffy The Vampire Slayer

Rupert Giles is the school librarian at Sunnydale High, but he's also got a secret — he's a Watcher, who guides Buffy on her journey to become the savior of the world. And he sometimes rolls up his sleeves and goes out to save the world on his own. Not to mention, Giles has another secret on top of that one — he's also Ripper, a ruthless, maybe slightly psycho, former wizard who's not afraid to get his hands a bit dirty. When there are nasty things that need to be done to keep us all safe, you won't have to look further than the book stacks at the high school to find the man to do them. (Thanks to WitnessAria for reminding me of this one.)

Wraith (Jennifer Maloy) in the Wild Cards universe

Jennifer Maloy is a shy, introverted librarian — until she discovers she's an Ace, with the ability to become insubstantial. Unfortunately, she can only carry a small amount of matter through walls, so her uniform as Wraith consists of a mask and a bikini. She steals from the rich and gives to the poor, and winds up battling crime lords and helping to solve the murder of Chrysalis. Art by Adam deKraker.

Haly in Libyrinth by Pearl North

In the distant future, the Libyrinth is a library so massive, people get lost in it and never come out, because it contains all the precious human knowledge saved from Earth. Haly is a clerk to the Libyrarian Selene, but she alone hears the books talking to her. She learns of a plot by the book-hating Eradicants to destroy the Libyrinth, and journeys with her friends to the Queen of Ilysies for help. But they get attacked, and Haly is forced to save the Libyrinth on her own.

The Psykers in Warhammer 40,000

The Psykers have powerful psychic abilities, which make them valuable allies but also leave them open to demonic possession or insanity. The most powerful and physically able psykers are chosen to serve as Librarians in the Space Marines, where they keep the records of the Chapter they belong to. They also help out in battle using their formidable abilities, and help to divide dangerous mutants from ones which might be useful to the Imperium. (Thanks to NinjaCyborg for suggesting this one.)

Karma in The X-Men

And finally, one more superhero librarian! Karma, a member of the New Mutants, works as a librarian at the University of Chicago, where she helps Kitty Pryde battle the anti-mutant hate group, Purity. Later, she goes back to Charles Xavier's Xavier Institute and works as the librarian there, also helping to mentor the students who are under 15 years old. She eventually starts teaching French and also serving advisor to the Alpha Squadron and the Lower School.

Additional reporting by Katharine Trendacosta. Thanks also to everyone who commented on this post.